Time Difference Calculator

Calculates the time units from one point in time to another. Based on a lenient gregorian calendar which, for example, interprets non existent June 31 as July 1, day of month 0 as the last day of the previous month, etc. The reset function presets a time zone having the same GMT offset as the current local time zone. Ungiven and not numeric inputs result in year 2000, day of month 1 and time values zero.